This invention deals with the field of agricultural seeders and in particular a method of reducing plugging of such seeders with crop residue and a guidance system for such planters.
In many areas, notably the Great Plains of North America, there has recently been a large shift to no-till seeding for crops such as cereals, pulses and oilseeds. These crops are usually xe2x80x9csolid-seededxe2x80x9d, which most often means seeded in narrow rows from 6 to 12 inches apart. Discer seeders do provide essentially an even coverage of the field with no discernable rows, however such seeders are not used to the extent they once were, due to the preference for no-till seeding. The crops, when growing, cover the ground and are harvested as if there are no rows. This differentiates such crops from xe2x80x9crowxe2x80x9d crops such as corn and cotton which are planted in wider rows, from 24 to 36 inches apart.
One of the objects of no-till seeding is to leave the previous years plant residue, or stubble, standing as long as possible to catch snow and later to provide protection for new seedling crops from wind and evaporation. It is common practice when harvesting to cut the crop as high as possible in order to leave as much standing stubble as possible to catch snow and to minimize the amount of non-grain material, mainly straw, passing through the combine harvester. The straw that does pass through the combine is generally broken up and spread evenly over the land.
The crop plants grow from a furrow which is generally depressed in the soil by packing. The next spring when no-till seeding is taking place, the rows of standing stubble therefore generally extend from a depressed furrow that is still easily discernible in the soil.
Present no-till seeders generally use a hoe opener for making the furrows into which seed is deposited, although disc furrow openers are used as well. The openers are mounted on a frame, which is generally towed by a tractor rather than mounted thereon as is common with row crop seeders seed and fertilizer is passed through a delivery system and into the furrows. Seed and fertilizer may be delivered as a mixture, or in separate tubes to different locations on one furrow opener or to separate furrow openers for seed and fertilizer. The fertilizer is sometimes applied in a separate field operation wherein no seed at all is being applied.
Hoe furrow openers are presently preferred over disc openers, as they generally penetrate better and do not require the cost and maintenance of bearings and so forth. Disc openers are also subject to xe2x80x9chair-pinningxe2x80x9d, wherein straw is not cut but instead is pushed into the furrow, causing poor germination of the seed and drying out the soil in the furrow by a wick, action. U.S. Pat. No. 5,619,939 discusses and provides an apparatus for alleviating this hair-pinning problem. Both hoe and disc furrow openers"" work better when they are passing through less crop residue. Straw tends to wrap around individual hoe openers and be dragged down the field, impairing the clean cut desired.
A major problem with hoe openers is that the standing stubble is often longer than the spacing between the furrow openers, and with hoe seeders it often does not pass between the openers, resulting in a wad of straw and plant residue being dragged down the field, plugging the seeder. Up until now, the only method used to alleviate this problem has been to provide more room for the straw and trash to move through between the hoe openers and between the frame and the ground. This has been done by increasing the spacing between the hoe openers, and thereby increasing the row spacing to 10 or 12 inches which is about the maximum spacing possible for these crops; by increasing the number of rows of hoe openers and thereby increasing the space between the hoe openers on a row; and finally by increasing the length of the hoe openers and thereby increasing the distance between the seeder frame and the ground.
When a seeder is seeding into standing stubble, the hoe openers constantly cross the standing stubble rows from the previous crop, knocking the stubble down. If the seeder was guided so that it only occasionally crossed a standing stubble row, such as when turning, much of the plugging problem could be alleviated, as the standing stubble rows would be left undisturbed and pass vertically under the seeder.
There is considerable prior art in the field of guidance systems to keep row crop implements aligned with furrows or plant rows. This is understandable because row spacing between passes must be kept constant at seeding in order to allow for efficient operation of subsequent cultivating, spraying and harvesting equipment. The prior art also provides guidance systems for working in growing row crops, where there is a sensor which senses the growing plant rows and keeps the implement between the rows. In solid-seeded crops, there has hitherto not been any perceived need for such precision since growing crops are not cultivated and sprayers and combines are operated without regard to where the narrow crop rows are located.
Guidance systems for use in row crops have not been used to guide an implement with respect to a row of standing stalks from the previous crop. There does not appear to have been any need for such guidance.
U.S. Pat. Nos. 5,255,756, 5,121,799, 5,094,300 and 5,031,704 are examples of such guidance systems for row crops. U.S. Pat. No. 5,148,873 provides a device to follow a furrow or growing crop row, thereby sending a signal to a guidance system.
It is the object of the present invention to provide a guidance system for a no-till seeder which will reduce the problem of plugging the seeder furrow openers with crop residue.
It is the further object of the present invention to provide such a guidance system for a no-till seeder which will reduce the amount of crop residue encountered by the furrow openers, thereby reducing straw dragging on hoe openers and hair-pinning of disc openers.
It is the further object of the present invention to provide such a guidance system for a no-till seeder which will leave a greater proportion of previous crop stubble standing after the seeding operation.
The present invention accomplishes these objects providing, in a no-till seeding application, a method of reducing plugging of seeders with crop residue from the previous year crop comprising the following steps: sensing the location of the standing stubble rows of the previous year crop; and guiding the furrow openers of the seeder between said standing stubble rows.
In a second aspect, the invention provides a guidance system for guiding a no-till seeder such that the furrow openers of said seeder travel along the field between the standing stubble rows from the previous crop, said guidance system comprising: sensing means to sense the standing stubble rows from the previous crop and to send a steering signal in response to changes in the relative position of the seeder to said standing stubble rows; and adjusting means to adjust the travel path of said seeder in response to said steering signals.
The standing stubble rows of the previous crop should have the same row spacing as the seeder being guided, or it will not be possible to have all furrow openers properly positioned is between the standing stubble rows.
Conveniently, the adjusting means could vary the path of travel of the seeder relative to the path of travel of the seeder towing vehicle.
In a third aspect the invention provides a guidance system for guiding a seeder towed by a vehicle, said guidance system sensing the location of the standing stubble rows left by a previous crop and in response to said sensing guiding the seeder so that the furrow openers of said seeder travel on a preferred path along the field between said standing stubble rows, said guidance system comprising: a row location sensor mounted on said seeder and adapted to sense the location of said standing stubble rows, said row location sensor sending a steering signal when said row location sensor senses that said furrow openers have deviated from said preferred path; a seeder position adjuster, said adjuster responsive to said steering signals; where in operation said row location sensor is in the neutral position when the furrow openers of said seeder are travelling on the preferred path between the standing stubble rows, and wherein when the seeder deviates from its preferred path said row location sensor sends a steering signal to said seeder position adjuster which causes said adjuster to move the seeder to one side or the other relative to the towing vehicle so as to direct said seeder back on to the preferred path.
The invention could further comprise a seeder position indicator viewable by the operator. The operator could then steer the towing vehicle to keep the row location sensor within its proper range of operation.
The seeder position adjuster could exert a force between the towing vehicle and the seeder and act to move the seeder to the right or left relative to the towing vehicle.
Where the towing vehicle is a tractor with a swinging draw-bar the seeder position adjuster could be a swinging draw-bar position adjuster and operate to move the swinging draw-bar right or left relative to the tractor.
Where the towing vehicle is not a tractor with a swinging draw-bar, such as when the towing vehicle is a tow-between air-seeder cart or where it is desired to provide a self-contained device, the seeder hitch could comprise a first hitch member attached to the towing vehicle, and a second hitch member engaged in the first hitch member such that the second hitch member may move laterally right or left with respect to the first hitch member when the seeder position adjuster is activated by the steering signals. The seeder position adjuster could conveniently comprise a hydraulic cylinder acting between the first and second hitch members wherein the hydraulic cylinder is activated by a solenoid valve receiving the steering signals.
Alternatively, the seeder hitch could include a laterally pivoting linkage and the seeder position adjuster could act on the pivoting linkage to move the seeder right or left relative to the towing vehicle. The seeder position adjuster could conveniently comprise a hydraulic cylinder acting on the linkage wherein the hydraulic cylinder is activated by a solenoid valve receiving the steering signals.
The row location sensor could sense the standing stubble rows of the previous crop by contact with the standing stubble rows which contact causes the row location sensor to move laterally to the right or left. The row location sensor could be a wedge-shaped pan sliding on the ground, the wedge-shaped pan having a width smaller than the spacing between standing stubble rows. A drag stabilizer attached to each side of the wedge-shaped pan would stabilise the pan, reducing bouncing when bumps are encountered and further helping to maintain its position between the standing stubble rows. A flexible link chain could be used as a drag stabilizer.
The wedge-shaped pan could be attached to a leg, and the leg could be attached to the seeder such that the leg may pivot vertically and laterally. Thus the pan could rise and fall vertically to follow contours or bumps in the ground, and the steering signal could be generated by the lateral angular position of the attachment. As the seeder veered off the preferred path wherein the furrow-openers are between the standing stubble rows, the leg would pivot laterally. This lateral movement could send a steering signal to the swinging draw-bar position adjuster.
The steering signals could be generated by a contact arm the proximate end of which is fixedly attached to the leg such that the distal end:of the contact arm is laterally between right and left signal points such that lateral movement of the leg and pan to the left causes the distal end to contact a left signal point, sending a steering signal to the seeder position adjuster adjusting the path of the seeder to the left, and such that lateral movement of the row location sensor to the right causes the distal end to contact a right signal point, sending a steering signal to the seeder position adjuster adjusting the path of the seeder to the right.
If the contact arm was flexible, damage to the signal points would be avoided. The flexible arm would also tend to position the row location sensor in the middle or neutral position when the seeder is raised for turns, since as the row location sensor swung to one direction, the flexible arm would bring it back and accelerate it to the centre neutral position.
Alternatively, the row location sensor could sense the furrow in the ground from which the standing stubble rows extend. The row location sensor could measure the distance from the seeder frame to the ground at two laterally spaced points and sense the difference between these two distances to determine the location of the furrow and thereby sense the location of the standing stubble rows. The row location sensor could use sonar or radar to determine the distances from the seeder frame to the ground.
Using mechanical means, the row location sensor could comprise first and second laterally spaced sensing elements adapted to ride along the ground, each of which may move vertically independently of the other, wherein the steering signals are generated by the vertical movement of one the sensing element relative to the other. The row location sensor could comprise a sensing element frame; the first sensing element pivotally attached to the sensing element frame about a horizontal axis substantially perpendicular to the direction of seeder travel such that the first sensing element may pivot up and down; the second sensing element pivotally attached, at a point laterally spaced from the first sensing element, to the sensing element frame about a horizontal axis substantially perpendicular to the direction of seeder travel such that the second sensing element may pivot up and down; a first contact element extending from the first sensing element in the direction of the second element; upper and lower second contact elements extending from the second sensing element in the direction of the first sensing element such that when the first sensing element moves up relative to the second sensing element, the first contact element comes in contact with the upper second contact element, sending a first steering signal to the seeder position adjuster, and such that when the first sensing element moves down relative to the second sensing element, the first contact element comes in contact with the lower second contact element, sending a second steering signal to the seeder position adjuster.
For increased efficiency of operation, the guidance system could further comprise a second row location sensor mounted on the seeder at a different location from the first row location sensor and adapted to sense the location of the standing stubble rows, and a control by which the operator may select which of the row location sensor guides the seeder, thereby allowing the operator to choose the row location sensor where the standing stubble rows or furrows are most suitable and avoid a row location sensor position where the standing stubble rows have been trampled by a previous field operation. Alternatively the sensor control could also allow both sensors to send steering signals, thereby allowing the seeder to be guided by both sensors at the same time.
The invention could further comprise a furrow sensor attached to the seeder such that the furrow sensor follows the end furrow of the last seeding pass thus acting as a marker to properly space the present seeder pass from the previous seeder pass, the furrow sensor sending a steering signal when the furrow sensor is moved perpendicular to the direction of seeder travel by the deviation of the seeder from the proper path, and further comprising a control whereby the operator can select which of the steering signals, that of the row location sensor or the furrow sensor, guides the seeder. With this arrangement, on turns the operator could align the seeder properly with respect to the previous pass using the furrow follower, and then switch the guidance control to allow the row follower to guide the seeder with the furrow openers between the rows.
Such a furrow sensor could comprise a curved tube adapted to follow the end furrow of the previous seeder pass, the tube attached to the seeder such that the tube may pivot vertically and laterally, and wherein the steering signal is generated by the lateral angular position of the attachment. Alternatively the row location sensor described above for sensing the furrow out of which the standing stubble rows extend could be used.
Where the previous crop was lentils or peas where there are no standing stubble rows, the furrow sensor could be used at all times to guide the seeder in proper relation to the previous pass.
It will be understood that in this application the word seeder is used in the generic sense to signify an agricultural implement that makes furrows in the soil and delivers seed or fertilizer or a combination thereof into the furrows.